Re: Low Tech Navigation

Richard D. Joffe (rdjoffe@erols.com)
Fri, 4 Dec 1998 20:04:59 -0500


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West Wight Potter Website at URL
http://www.lesbois.com/wwpotter/
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-----Original Message-----
From: Bill Blohm <bblohm@boi.hp.com>
To: wwpotter@tscnet.com <wwpotter@tscnet.com>
Date: Tuesday, November 24, 1998 3:09 PM
Subject: Re: Low Tech Navigation

>Here's a toss-in: A question for Nav 101 levels:
>How can you tell the latitude you're at if you were to
>be taken out of your office or home right now, no chance
>to get anything, and all you've gotten on you is what
>you can use. You're taken out into the woods somewhere
>on Earth. What's your latitude?

90 degrees minus the sun's height above the horizon at noon is your
latitude. It should be directly overhead at the equator and on the horizon
at the poles. This is only true at the equinoxes (first days of Spring and
Autumn). I believe the sun's height will vary 23 1/2 degrees above or below
the latitude, being 23 1/2 degrees above the true latitude at the Summer
Solstice (first day of Summer), and 23 1/2 degrees below at the Winter
Solstice (first day of Winter).

To determine when it's noon without a watch, put a stick in the ground and
follow the shadow. When the shadow is shortest, it will be noon, and the
shadow will point to true North.

Extra credit: You may also use the height of the North Star (Polaris) above
the horizon. It should be directly overhead (90 degrees) at the North Pole
on the equinoxes, and on the horizon at the equator. On any other day,
you've have to make an adjustment.

Richard D. Joffe
rdjoffe@erols.com
P-15 #2080, "Potter Noster"
Columbia, MD

P.S. I'm late on reading my e-mail, so someone else may have already rung in
before me, and no, Alex, I didn't phrase the answer in the form of a
question. :-) (Jeopardy joke)